Prior to the present invention, 2,3,5-trimethylphenol was prepared from a mixture of isophorone and methanol by contacting the mixture with an alumina, chromium oxide and potassium oxide catalyst at a temperature of 630.degree. C. It would be desirable to synthesize polymethylated phenols from a mixture of isophorone and methanol at a substantially reduced temperature.
The present invention is based on the discovery that polymethylated phenols having the formula ##STR1## can be made by contacting a mixture of isophorone and methanol with the calcination residue of a mixture of magnesium carbonate and/or magnesium hydroxide and manganese hydroxide at a temperature in the range of from about 400.degree. C. to 550.degree. C., where R and R.sup.1 are members selected from hydrogen and methyl.